First breeding record of the black‐headed penduline tit (Remiz macronyx) in China

Abstract Black‐headed penduline tit (Remiz macronyx) is a poorly known bird species mainly distributed in Iran, Turkmenistan, and Kazakhstan. The distribution of black‐headed penduline tit is disjointed and fragmented, and it occurs only along lakes or rivers surrounded by extensive reedbeds. Four subspecies of R. macronyx have been recognized (macronyx, neglectus, nigricans, and ssaposhnikowi). The ssaposhnikowi subspecies was previously known to occur only around lakes in southeastern Kazakhstan. In this study, we reported the first confirmed breeding record of R. m. ssaposhnikowi in the Nalati wetland, Ili, Xinjiang, China, extending the distribution range of the black‐headed penduline tit by 350 km to the east. We also obtained new information about the morphology and breeding behavior of R. m. ssaposhnikowi, which can be useful for the taxonomy of penduline tits, especially in distinguishing black‐headed penduline tits from Eurasian penduline tits (R. pendulinus).

The ssaposhnikowi subspecies is rare and variable in morphology, whether it should be recognized as a separate subspecies is controversial (Bot & Van Dijk, 2009;Svensson & Shirihai, 2018;Vaurie, 1957). To date, most records of this subspecies are found in the Ili River basin, and the easternmost known distribution in the Ili River basin is Burundysu (Figure 1; 43°42′N 78°39′E), Almaty Province, Kazakhstan (Gavrilov & Gavrilov, 2005). We speculated that this subspecies may occur in Ili, Xinjiang, China, where the Ili River originates and a similar habitat occurs. In this study, we conducted several field trips upstream of the Ili River in search of the black-headed penduline tit, and this species was discovered in China in 2022. We also acquired valuable data about its morphology, breeding behavior, and taxonomy during the field expeditions.

| The record site, habitat, and population size
From May to July 2022, black-headed penduline tits were found in the reedbeds in the Nalati wetland, Xinyuan County, Ili Prefecture, Xinjiang, China (Figure 1). The Nalati wetland is located along the Künes River, which merges with the Tekes River and other rivers to form the Ili River.
The area of the Nalati wetlands is very large, including the Nalati National Wetland Park (43°30′N 82°42′E) and several lakes around it. The Nalati National Wetland Park has a total planned area of 140.52 km 2 , of which 139.45 km 2 are wetlands with landscapes such as rivers, swamps, lakes, and meadows. There are extensive reeds (Phragmites australis) that are suitable for the breeding of blackheaded penduline tits (Figure 2a). Birds in Nalati National Wetland Park seem quite common; we surveyed a small area (less than 1.5 km) of the park by tourist boat and saw more than 20 birds in 30 min. In addition, another 11 birds (eight males, one female, and two juveniles) were found in a small lake (named Zhongyangchang Lake, 0.4 km 2 in size, 43°33′N 82°43′E) 3 km north of the park, which is surrounded by sparse reeds (Figure 2b).

| Appearance and measurements
We caught five males in Zhongyangchang Lake by a mist net (6 m × 3 m) setting close to the reeds. A playback of black-headed penduline tit call (downloaded from https://xeno-canto.org/) was used to attract the birds. All trapped birds were marked by four color rings and photographed in standard manners with a camera (Canon 5D Mark III with a 50 mm lens). Six morphometric traits (weight, bill length, tarsus length, wing length, tail length, and body length) were measured before the bird was released in the field. The morphometric traits of the five males are listed in Table 1. All the males had a black mask, a chestnut-brown crown, and nape, and most of them had a whitish throat (Figure 3a), except F I G U R E 1 Distribution of the black-headed penduline tit (Remiz macronyxv). The range in green comes from BirdLife International. The red star marks the location of the Nalati wetland, China.
one who had a sooty black throat and upper breast ( Figure 3b). The mantle and scapulars were deeply dark red-brown, and the flight feathers had broad white fringes, creating a white wing panel; the underparts were buff. Female is similar to male but less well marked and has a wide black mask, a clear red-brown fringe on the head above the forehead patch extending to both sides of the crown.
However, the red-brown area in the head is smaller in females than in males, and the mantle and scapula are paler in females than in males ( Figure 3c). On 28 July, the last time we visited the lake, we saw two juveniles foraging in the reedbeds together. They have large feet like the adults, but the head and upper parts are dull grayish, and the underparts are light buff (Figure 3d). Given these morphological features and its close distribution to the black-headed penduline tits ( Figure 1), the birds we found in the Nalati wetland are supposed to be the ssaposhnikowi subspecies of black-headed penduline tits.

| Nests and breeding behavior
We found four nests in Zhongyangchang Lake. The minimum dis-

| DISCUSS ION
This study is the first to confirm R. m. ssaposhnikowi breeding in the Nalati wetland, Ili Prefecture, Xinjiang, China, which is 350 km east of the known easternmost distribution along the Ili River basin in Burundysu, Kazakhstan ( Figure 1). Thus, our findings extended the eastern distribution range of black-headed penduline tits. Blackheaded penduline tits in Nalati National Wetland Park seem common, with more than 20 birds in an informal 1.5 km boat survey, where more than 100 km 2 reedbeds are in this wetland. By contrast, Bot and Van Dijk (2009) reported that the population of R. m. ssaposhnikowi in Topar Lakes appeared to be of low density, and only 14 birds were found. The reedbeds in Topar Lakes are sparse and discontinuous, similar to those in Zhongyangchang Lake ( Figure 2b).
Overall, R. m. ssaposhnikowi prefers extensive reedbeds, and it can also breed in lakes or rivers with sparse reedbeds.
Penduline tits are famous for their delicate nests. All species in genus Remiz built a domed nest with a tube at the side ( Figure 4).
Nests can be divided into three types based on their location and shape: building a nest in a tree (tree nest, Figure 4d,e), building a nest between two reed stems (reed nest, Figure 4a-c), and building a tree nest-like nest between two reed stems (transitional nest) (Burckhardt, 1948). There are several differences between the reed nest and tree nest. First, the reed nest was shaped like a cylinder, whereas the tree nest was shaped like a pear. Second, the reed TA B L E 1 Measurements of five Remiz macronyx ssaposhnikowi males trapped during the research period; one individual did not have its tail length and body length measured due to molting.

Morphometric characters
Mean ( nests are built between two parallel reed stems "tied" together with Another attractive feature of penduline tits is their variable pa-  Figure 3d). Furthermore, none of the birds we saw in Nalati had an entire black head like R. m. macronyx. There was one bird whose throat and upper breast were black (Figure 3b), but the morphometric characteristics and behavior were not different from those of the other groups. In addition, all R. m. ssaposhnikowi in Nalati built reed nests, whereas R. p. caspius always built tree nests. Overall, the ssaposhnikowi in Nalati is morphologically and behaviorally different from R. p. caspius and has plumage characteristics unique to other black-headed penduline tits subspecies. It should be treated as a separate subspecies of the black-headed penduline tit.
The taxonomy of the black-headed penduline tit is still controversial. Previous research has combined all penduline tits into one wide-ranging polytypic species, Remiz pendulinus, while others have divided it into four species (Eck & Martens, 2006;Harrap, 1996;Madge, 2008 Vaurie, 1957). It is hoped that our observations will prompt researchers to conduct more in-depth studies of this group, including high-throughput genome-scale sequencing data in combination with phenotypic data, which will help to determine the hybridization and evolutionary relationships between these populations.
Black-headed penduline tit is one of the most poorly known bird species, with only 60 records worldwide on eBird (eBird, 2023).
Recent studies have reported the westernmost record of the blackheaded penduline tit in Turkey (Kittelberger et al., 2022), and our study extends the easternmost distribution of this species in the Ili River basin, which implies that our current knowledge of the distribution of the black-headed penduline tit is still limited. We recommend that other field researchers or bird watchers search for or pay more attention to this species in future fieldwork. writing -review and editing (supporting).

DATA AVA I L A B I L I T Y S TAT E M E N T
Data sharing not applicable to this article as no datasets were analysed during the current study.